- ID:
- ivo://CDS.VizieR/J/AJ/109/853
- Title:
- VLA survey of Abell clusters. IV.
- Short Name:
- J/AJ/109/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourth in a series of papers describing an in depth study of a large statistical sample of radio galaxies in Abell clusters. This sample forms the basis of a detailed optical and radio study of the host galaxy properties, environments, and evolutionary models for radio galaxies as a class of objects. In this paper, we examine the radio detection statistics as a function of cluster morphological type, galaxy richness, and spatial location within the cluster galaxy distribution. These relationships are also parametrized as a function of radio power. The spatial distributions of the radio sources as a function of distance from the cluster center indicate that radio galaxies are preferentially located at small radii from the center of the cluster potential. This is observed as a factor of 2-3 excess over that predicted by a King-model surface-density distribution. The excess is higher in the upper radio power bin. This result is easily explained, however, from the spatial distribution of the brightest galaxies and the relationship between radio and optical luminosity. The sample is divided into richness classes 0, 1, and 2, according to Abell's criterion, and in two radio power ranges. While simple counting shows that richer clusters have more radio galaxies in both radio power bins, when the detections are scaled to the number of galaxies surveyed in each cluster, no significant correlations are found. This result implies that the number of radio galaxies detected simply scales with the number of galaxies surveyed. The higher galaxy density (and presumably higher ICM gas density) in richer clusters does not appear to affect the rate of radio source formation. The clusters are divided into Rood-Sastry and Bautz-Morgan morphological types. While it would appear that the more regular clusters have higher radio detection rates, when the classes are normalized to the number of galaxies, the radio detection rates are found to be identical regardless of cluster morphology. In conclusion, it is the optical properties of the host galaxy which most influence both the radio detection rate and the radio source properties. The cluster properties, galaxy density, and spatial location of the galaxy do not significantly affect the observed radio statistics.
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- ID:
- ivo://CDS.VizieR/J/AJ/98/64
- Title:
- VLA survey of Abell clusters of galaxies I.
- Short Name:
- J/AJ/98/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a VLA survey at 20cm of a complete sample of nearby Abell clusters (D<=3). We have compiled an extensive catalog of cluster radio sources with S_20_>10mJy from a combination of our VLA observations and observations of similar resolution with the Westerbork Synthesis Radio Telescope (WSRT). Using these radio data and X-ray data from the Einstein observatory, we have analyzed the properties of these clusters. Unlike that previously suggested, no significant correlation is found between 20cm radio power and X-ray luminosity. There is weak evidence that richer clusters have a higher probability of radio emission. Based on Rood-Sastry morphological types of clusters, we do not find any strong evidence that regular-type clusters are statistically more likely to be radio loud than irregular-type clusters. However, Bautz-Morgan types I and II-III are found to have comparable radio-detection rates; but Bautz-Morgan Type III clusters are likely to have a lower radio-detection rate. A weak correlation between X-ray-cooling mass-accretion rates and radio powers was found for central, dominant galaxies in cooling-flow clusters. This might suggest that either cooling accretion directly fuels the central engine and/or cooling flows strongly interact with (e.g., confine) the radio plasma. In addition, radio sources associated with central dominant galaxies in cooling-flow clusters tend to be small in comparison with those in non-cooling-flow clusters. This might suggest that cooling flows tend to obstruct the propagation of radio jets from central, dominant galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/110/1959
- Title:
- VLA survey of Abell clusters. V.
- Short Name:
- J/AJ/110/1959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a program of optical imaging of 265 radio galaxies in rich clusters. Using isophotal surface photometry, we investigate the optical properties such as the morphology, surface-brightness profiles, surface-brightness/size relationships, ellipticities, and the frequency of nonelliptical isophotes. The results are compared to a "normal" nonradio-selected sample of elliptical galaxies from the same clusters. The goal is to determine if the parent population of FR I radio galaxies can be distinguished optically from radio-quiet galaxies. The results of the analysis are that cluster ellipticals are a very homogeneous class of objects. The optical properties are consistent with a one-parameter family, where the optical luminosity is the fundamental parameter. In all tests considered, radio-loud FR I galaxies cannot be distinguished optically from radio-quiet galaxies selected from the same environment. The local density of nearby companions (<20kpc) and the frequency of morphological peculiarities or tidal interactions are not statistically different between the radio-loud and quiet samples. There is some suggestion from comparison to published samples of non-cluster radio galaxies, that the cluster environment is not condusive to long-lived tidal interactions, and that such events may be more important to galaxy evolution in poor groups and lower density environments. Such events appear to have little influence on the formation of FR I radio galaxies in rich clusters. The results are consistent with the idea that all elliptical galaxies may at some time (or many times) contain powerful (FR I) radio sources.
22944. VLA survey of CDF-S. II.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/95
- Title:
- VLA survey of CDF-S. II.
- Short Name:
- J/ApJS/179/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the optical and infrared identifications of the 266 radio sources detected at 20cm with the Very Large Array in the Chandra Deep Field-South. Using deep i-band Advanced Camera for Surveys, R-band Wide Field Imager, K-band SOFI NTT, K-band ISAAC VLT and Spitzer imaging data, we are able to find reliable counterparts for 254 (~95%) VLA sources. Twelve radio sources remain unidentified, and three of them are "empty fields". Using literature and our own data we are able to assign redshifts to 186 (~70%) radio sources: 108 are spectroscopic redshifts and 78 are reliable photometric redshifts. Based on the rest-frame colors and morphological distributions of the host galaxies, we find evidences for a change in the submillijansky radio source population: (1) above ~0.08mJy early-type galaxies are dominating and (2) at flux densities below ~0.08mJy, starburst galaxies become dominant.
22945. VLA survey of CDF-S. III.
- ID:
- ivo://CDS.VizieR/J/ApJ/698/740
- Title:
- VLA survey of CDF-S. III.
- Short Name:
- J/ApJ/698/740
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the X-ray properties of the radio sources detected in a deep 1.4 and 5GHz VLA Radio survey of the Extended Chandra Deep Field-South (E-CDFS). Among the 266 radio sources detected, we find 89 sources (1/3 of the total) with X-ray counterparts in the catalog of the 1Ms exposure of the central 0.08deg^2^ or in the catalog of the 250ks exposure of the 0.3deg^2^ E-CDFS field. For 76 (85%) of these sources, we have spectroscopic or photometric redshifts, and therefore we are able to derive their intrinsic properties from X-ray spectral analysis, namely intrinsic absorption and total X-ray luminosities. We find that the population of submillijansky radio sources with X-ray counterparts is composed of a mix of roughly 1/3 star-forming galaxies and 2/3 active galactic nuclei (AGNs).
- ID:
- ivo://nasa.heasarc/vlacdfscat
- Title:
- VLA Survey of Chandra Deep Field South
- Short Name:
- VLACDFSCAT
- Date:
- 21 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from 20 and 6 cm VLA deep observations of the Chandra Deep Field-South (CDF-S), including the Extended CDF-S (E-CDF-S). In the reference paper, the authors discuss the radio properties of 266 cataloged radio sources, of which 198 are above a 20-cm completeness level reaching down to 43 microJanskies (µJy) at the center of the field. Survey observations made at 6 cm over a more limited region cover the original CDF-S to a comparable level of sensitivity as the 20-cm observations. Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a further 37 have counterparts in the E-CDF-S area not covered by the 1 Ms exposure. Using a wide range of material, the authors have found optical or infrared counterparts for 254 radio sources, of which 186 have either spectroscopic or photometric redshifts. Three radio sources have no apparent counterpart at any other wavelength. Measurements of the 20-cm radio flux density at the position of each CDF-S X-ray source detected a further 30 radio sources (not included in this table) above a conservative 3-sigma detection limit. X-ray and sub-millimeter observations have been traditionally used as a measure of AGN and star formation activity, respectively. These new observations probe the faint end of both the star formation and radio galaxy/AGN population, as well as the connection between the formation and evolution of stars and SMBHs. Both of the corresponding gravitational and nuclear fusion-driven energy sources can lead to radio synchrotron emission. AGN and radio galaxies dominate at high flux densities. Although emission from star formation becomes more prominent at the microJansky levels reached by deep radio surveys, even for the weakest sources, an apparent significant contribution from low-luminosity AGN as well as from star formation is still found. Notice that are 319 entries in this table corresponding to the 266 catalogued radio sources, due to the fact that some of these sources have multiple components. In such cases, the composite source as well as each of its components are listed as separate entries, e.g., source 7 which has 3 components (A, B and C) has 4 entries in this table. This table was created by the HEASARC in November 2008 based on the electronic version of Table 1 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/AJ/113/1939
- Title:
- VLA Survey of Hercules cluster. I.
- Short Name:
- J/AJ/113/1939
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents results from a survey of lambda 21-cm emission from galaxies in the Hercules cluster, A2151 and A2147. Four VLA primary beam areas were covered, a total area of 0.9 square degrees, including some 120 spiral galaxies brighter than 17.5m. The velocity resolution is 44km/s, the angular resolution 25". The detection threshold at field center is 2.6x10^8 h^{-2}M_{sun}_ in H I mass or about 1.8x10^20cm^-2^ in column density. There are 61 galaxies detected in H I, of which about 25 had been previously detected at lambda 21-cm. About ten of the detections correspond to galaxies that are very faint in the optical, m_E_>=18 or M>=-17mag-5logh. Some of these low surface brightness galaxies have very extended H I disks, with r>=15kpc. The abundance of H I is a strong function of position in the cluster, with galaxies in the south and west showing hardly any gas, and galaxies in the north and east of A2151 frequently having massive, extended gas disks. The morphology of the remnants of gas in galaxies in the south and west suggests that the intracluster medium is responsible for their H I deficiency, but there are also several dramatic galaxy mergers in progress. (c) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/VIII/50
- Title:
- VLA Survey of Rich Clusters of Galaxies
- Short Name:
- VIII/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed 60 fields towards 57 Abell and one Zwicky cluster of galaxies using the Very Large Array (VLA) with scaled arrays at 1.5 and 4.9 GHz. The source catalogue contains radio and optical parameters for 994 sources up to a lower flux limit of 1.0 mJy at 1.5 GHz and comprises a complete sample above 2.5 mJy. The combined sky area within the half-power circle on the maps is 3.5x10^-3^ sr, and the cluster fields are distributed between +35 deg and -30 deg declination. The source catalogue list positions, angular size, spectral index and optical identification, magnitude and morphology, if available.
22949. VLA survey of the CDF-S I.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/71
- Title:
- VLA survey of the CDF-S I.
- Short Name:
- J/ApJS/179/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 20 and 6cm VLA deep observations of the CDF-S including the Extended CDF-S. We discuss the radio properties of 266 cataloged radio sources, of which 198 are above a 20cm completeness level reaching down to 43uJy at the center of the field. Survey observations made at 6cm over a more limited region cover the original CDF-S to a comparable level of sensitivity as the 20cm observations. Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a further 37 have counterparts in the E-CDF-S area not covered by the 1Ms exposure. Using a wide range of material, we have found optical or infrared counterparts for 254 radio sources, of which 186 have either spectroscopic or photometric redshifts. Three radio sources have no apparent counterpart at any other wavelength. Measurements of the 20cm radio flux density at the position of each CDF-S X-ray source detected a further 30 radio sources above a conservative 3{sigma} detection limit. X-ray and submillimeter observations have been traditionally used as a measure of AGN and star formation activity, respectively. These new observations probe the faint end of both the star formation and radio galaxy/AGN population, as well as the connection between the formation and evolution of stars and SMBHs.
- ID:
- ivo://nasa.heasarc/vlasdf90cm
- Title:
- VLA SWIRE Deep Field 90-cm Source Catalog
- Short Name:
- VLASDF90CM
- Date:
- 21 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from the deepest radio continuum surveys to date at a radio wavelength of >~ 1m. The observations were taken with the VLA at 324.5 MHz covering a region of the SWIRE Spitzer Legacy survey, centered at RA and Dec of 10:46:00, +59:01:00 (J2000). The data reduction and analysis are described in the reference paper and a catalog of the sources detected above 5 sigma is presented herein. The authors also discuss the observed angular size distribution for the sample in their paper, and, using their deeper 20-cm survey of the same field (Owen and Morrison 2008, AJ, 136, 1889), they calculate spectral indices for sources detected in both surveys. They report log N-log S counts at 90 cm which show a flattening below 5 mJy. Given the median redshift of the population, z ~ 1, the spectral flattening and the flattening of the log N-log S counts occur at radio luminosities normally associated with AGN rather than with galaxies dominated by star formation. Observations were made of a single pointing center position (given above), with the VLA in A and C configurations for a total of almost 85 hours on-source between 2006 February and 2007 January. However, due to the ongoing EVLA upgrade, only 22 working antennae were typically avaliable in A and 18 in C. Thus, the total integration time was equivalent to ~ 63 hours in A and even less in C, with correspondingly less u-v coverage. This table was created by the HEASARC in September 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/137/4846/">CDS catalog J/AJ/137/4846/</a> file table2.dat. This is a service provided by NASA HEASARC .
